Adjustable work pick-up device

ABSTRACT

A device for picking up and transferring single plies of sheet material, especially a wide variety of fabric and the like which may be in a stack, comprising a presser foot, a relatively movable work-pinching member cooperative with the presser foot, and means for adjusting the nip of the member and the foot. Threaded means adjustably limits the extent of initial separation of the pinching member and the foot whereby appropriate nipping of different thicknesses and types of material is obtained.

United States Patent [191 Stewart et al.

ADJUSTABLE WORK PICK-UP DEVICE Inventors: James B. Stewart; Carlton G.Lutts,

both of Salem, Mass.

Assignee: USM Corporation, Flemington, NJ.

Filed: June 6, 1972 App]. No.: 260,304

US. Cl. 271/19, 271/18 Int. Cl. B65h 3/12 Field of Search 271/18, I9,20, 21,

References Cited UNITED STATES PATENTS 5/1966 Southwell et al. 27l/l911/1967 Smith et al 271/25 X Aliv- July 24, 1973 3,588,091 6/l97l Stoneet al 271/19 Primary Examiner-Even C. Blunk Assistant Examiner-Brucel-l. Stoner, Jr. Attorney-Carl E. Johnson et al.

nipping of different thicknesses and types of material is obtained.

2 Claims, 6 Drawing Figures PAIENIEU JUL 2 4:915

I Mu ADJUSTABLE WORK PICK-UP DEVICE CROSS REFERENCE TO RELATEDAPPLICATION Concurrently herewith another application, Ser. No. 260,306filed June 6, 1972, is being filed with Mr. Carlton Lutts and Mr. JamesStewart as joint inventors and pertaining to the ply separation meansillustrated in the present application. A further concurrentapplication, Ser. No. 260,305 filed June 6, 1972 filed in the name of R.R. Walton et a1. relates to the pick-up construction shown herein.

BACKGROUND OF THE INVENTION A need exists for a versatile pick-up devicecapable of automatically moving successive individual plies of fabricand the like from an external portion, for instance the top, of a stackand preferably without disturbing the position of an adjacent orunderlying ply in the stack. The problem is difficult of solution inreliable manner, and often because there may exist a cleavage of fibersin the interface region. Suction has frequently been employed incombination with other elements such as card cloth or bristles forpenetrating work pieces. When they are pervious to air flow theunderlying ply is or may be disturbed, and excessive penetration of thework by the pointed means can have a like effect. Need for a precisionmechanism for controlling movement of the pointed elements and theirinitial separation from a cooperative ply-nipping member is recognizedin the copending Walton application above cited.

SUMMARY OF THE INVENTION In view of the foregoing it is a main object ofthis invention to provide, for use in a work transferring machine, apick-up device of cooperating jaw type construction, and jaw adjustingmechanism enabling the jaws to be effective on a range of flaccid sheetmaterial for mechanically seizing and lifting a locality of an externalply of a stack of flexible work pieces without affecting an underply.

Another object of the invention is to provide jaw actuating mechanismincluding easily adjustable means controlling the degree of jawseparation whereby a localized portion of the exposed sheet of a stackof limp plies can enter between the jaws and be seized and folded onitself during lift-off and transfer.

In accordance with these objects, a feature of the invention resides inthe provision, in combination with mounting means for a pickup dvicedevice a presser foot for bulging or puckering an exposed locality of aply, and a pivotal pawl yieldingly cooperative with said foot forclamping a portion of the puckered locality upon the jaw surface, of apinch adjusting nut threaded on the mounting means and having cammingengagement with the pawl to control its spacing from the presser foot.

BRIEF DESCRIPTION OF THE DRAWINGS The foregoing and other features ofthe invention will now be more particularly described in connection withan illustrative fabric pick-up device and with reference to theaccompanying drawings thereof, in which:

FIG. 1 is a view in side elevation of a pick-up and ply separatingassembly in initial work engaging condition;

FIG. 2 is a bottom view of the pick-up portion,

FIG. 3 is an axial section showing a pincer of the pick-up device withits adjustable nip controlling means in work seizing position over astack;

FIG. 4 is a view similar to FIG. 1 but showing the pick-up rotated byits ply separating mechanism;

FIG. 5 is a transverse section taken on the line V-V of FIG. 3indicating nut means for adjustably limiting the stroke of the pincer,and

FIG. 6 is a detail view of an adjustable detent for controllingfriction.

DESCRIPTION OF PREFERRED EMBODIMENT A machine of the general type forautomatically feeding fabric sheets W or the like from the top of astack S is illustrated and described in U. S. Letters Patent No.3,531,103 issued Sept 29, 1970, in the name of R. R. Walton. Theparticular pick-off devices therein rely on suction as does theadjustable pick-off means disclosed, for instance, in U. S. LettersPatent No. 3,550,932 issued Dec. 29, 1970 in the name of R. C. Mason.The present invention provides an adjustable mechanical pick-up devicegenerally designated 10 (FIGS. 1, 3) which is herein illustrated asemployed in a fabric transfer machine (not shown) in combination with afluid pressure operated ply separating mechanism generally designated14, the assemblage 10, 14 (FIG. 4) being shown by way of example only asadjustably mounted on a movable carrier 16 (FIG. 1) of the machine as,for instance, in the manner disclosed in the cited Mason Patent. It willbe understood that, according to the size, shape, and weight of the workpieces W to be transferred, one or a plurality of the assemblages 10, 14may be mounted in any selected pattern on the carrier 16 as needed.

The pick-up device 10 herein claimed may be operated in combination withother ply separating mechanism, and the ply separating mechanism 14claimed in the cited concurrently filed Lutts et a1 application may beoperated in combination with other pick-up devices. It will beunderstood the plies W to be transferred may be top, bottom or otherwiseexternally exposed with respect to a stack.

For detachably and slidably supporting the assemblage l0, 14 a tubularbody 18 FIG. 1) has a threaded stem at its upper end extending through aslot in the carrier 16 for receiving a thumb nut 20. The body 18 isformed with ports 22, 24 (FIG. 1) and a partly helical slot 26 forpurposes later explained. Slidable axially in the body 18 is a piston 28having a radial hole the wall of which is threaded for receiving a campin 32 slidably extending through the slot 26. As shown in FIG. 1 theupper portion of the slot 26 is longitudinal and the lower portionextends helically at about 45, relative heightwise and turning movementof the piston 28 being thus limited. A head 34 of the piston is disposedat the lower end of an upper chamber 36 in the body 18 havingcommunication with the port 22, and a lower chamber 38 in the pistoncommunicates with the port 24 via a hole 40 in the wall of the piston 28when the latter is in its relatively lower position, the hole 40 beingeffectively closed by the wall of the body 18 when the piston 28 isrelatively raised as shown in FIG. 4.

Within the lower end of the piston 28, a cylindrical stem of a presserfoot 42 is axially slidable within limits, being secured by a set screw44 (FIG. 1) extending through a longitudinal slot 46 in the piston andthreaded into the stem. As shown in FIGS. l-3, a work engageableperipheral portion 48 of the presser foot is eccentrically enlarged andcircular, and centralized with respect to a diameteric slot 50. Securedin this slot by a set screw 52 is a V-shaped tooth 54 having itsbevelled faces 56, 56 receding in the slot and extending upwardly todefine a shelf portion 58 having an apex slightly above the workengaging surface 48. For cooperating with the presser foot 42 thepick-up device 10 includes a pinch pawl 60. The pawl 60 has pin 62 andslot 64 connection in a heightwise kerf in the presser foot 42, thearrangement being such that a pair of parallel rows of pointed andbiased teeth 66 arcuately disposed on the underside of the pawl 60 arerespectively movable in their planes to engage the top sheet W in thelocality P (FIGS. 1, 3) where it may have been bulged or puckered by thecompressive action of the presser foot portion 48 and, by means nextexplained, gather the localized portion in pinching relation onto theshelf portion 58, as shown in FIG. 3.

Adjustably threaded onto the lower end of the piston 28 is a pinchadjusting ring nut 70 (FIGS. 1, 3) having internally a circular camminglip 72 (FIG. 3). A leaf spring 74 is secured at one end to the pawl 60and has a free downwardly extending portion engageable with an innerface76 of the presser foot 42 to urge the pawl toward its open orinoperative position. The spring 74 accordingly yieldingly resistsmovement of the teeth 66 toward pinching relation with the presser foot42, and more positive pinching is effected as the lip 72 is relativelylowered by the piston to cam the pawl 66 toward the shelf portion 58 bymechanism later explained. The ring nut 70 at 90 spacings is semi-boredas at 76 (FIG. both radially and longitudinal to provide fouralternative positions for mating with a cut-away portion 77 in thepiston 28 and thus accommodating a pinch control lock pin 78. It will beunderstood that the pin 78 is detachable and insertable to lock the ringnut in the particular 90 rotational setting affording best results forthe heightwise position of the lip 72, a relatively higher lip generallypermitting a wider initial nipping position for pinching thicker or moresubstantial work pieces. Viewed alternatively, for dealing with verythin sheet material, refined adjustment by means of the ring nut 70insures that only a single ply will be seized.

Preferably, the degree of friction between the presser foot stem and thepiston 28 is adjustably controlled better to accommodate different typesof work pieces W and insure that the top piece will be suitably puckeredabout the shelf portion 58, for instance as illustrated at P (FIGS. 1and 3). To this end, and as herein shown in FIG. 6, for instance, aspring-pressed ball detent 80 engaging the interior wall of the piston28 is nested in the presser foot stem and backed by an adjustable setscrew 82. It will be understood that threading the screw 82 inwardly toincrease friction will cause the presser foot 42 to react harder on thestack S before relatively yielding upwardly.

In operation of the fabric transferring machine relative movement ofapproach of the stack S and the pickup device is in this case effectedby raising the stack by a cyclical elevator mechanism 83 (FIG. 1) untila penumatic sensor in the form ofa tube 84 (FIGS. 1 and 3) signals forstack lowering (following a time delay) after the top ply has beeninitially engaged as shown in FIG. 1. The chamber 38 is then open toexhaust, and

a low pressure (roughly on the average of about pounds per square inch)provided in the chamber 36 is then only adequate to nearlycounterbalance a tension spring 86 interconnecting the carrier 16 andthe pin 32. As shown in FIG. 1 the sensor tube 84 is slidably mounted ina vertical guide sleeve 88 fixed in a collar 90 secured on the piston28. The tube 84 is disposed to be blocked at its lower end by thepresser foot 42 approaching an upper limit as shown in FIG. 3. Air flowdownwardly in a flexible supply line 92 connected to the tube 84 is thusstopped and the resultant signal, in addition to stopping elevation ofthe stack S, also signals for operation of the ply separating mechanism14 by dumping pressure from the chamber 36 whereupon the spring 86 atonce causes lifting and rotation of the piston 28 and likewise of thepresser foot 42 for effecting separation of the picked-up top ply. Theupward displacement of the sensor tube 84 is against resistance of areturn spring 94.

Reverting to a more detailed consideration of operation of the pick-updevice 10, which functions prior to rotation about a vertical axis, asthe stack S is elevated the presser foot 42 yields upwardly withresistance as suitably selected to compress and thereby bulge or puckera locality of the top ply W as at P eccentrically of the piston 28 thuscausing an irreguar and somewhat annular wave in the top sheetimmediately beneath the open pincer teeth 66 to come into engagementtherewith at each side of the apex of the shelf 58. The pawl 60, as thepresser foot is relatively raise in the piston 28, is cammed by the lip72 to pinch the puckered portion upon the shelf 58. In this action therows of teeth 66 first urge the workagainst the V-tooth point and thenrise further as allowed by the slot 64 to move past that point on itsopposite sides to hold a small work portion folded and clamped uponitself. Only the single top ply is thus pinched.

Upon actuation by the spring 86 as aforesaid, the piston 28 is raisedfollowing pick-up and, by means of the cam pin 32 of the ply separatingmechanism 14, rotaeed rotated as viewed from above and shown in FIG. 4.Thus at one or more selected localities the seized work is subjected tolocalized twisting to disrupt cleavage of interfacial fibers. It will beunderstood that certain pairs of the assemblies 10-14 may providetwisting in opposite direction, their slots 26 in such cases beingoppositely inclined helically in order to provide desired stresspatterns such as suggested in FIGS. 2 and 3 considered most effectivefor insuring that an underply is not disturbed as the top ply alone isseparated and relatively raised.

The assemblies 10-14 are now jointly moved by the carrier 16 tolaterally position the work over a selected delivery position. At theend of this lateral feeding stroke a switch (not shown) is actuated topressurize the upper chamber 36 to a degree considerably higher thanpreviously. This forces the piston 28 downward against influence of thespring 86 to return the cam pin 32 to the bottom of its slot 26. Thedownward movement of the piston and its resultant rotation to unstressthe ply then being carried open the port 40 to let air under pressurethrough the port 24 and into the chamber 38. As a consequence thepresser foot 42 is abruptly forced downwardly to enable the pawl 60 tobe freed by inertia and thus causes the supported top ply to be releasedfor delivery.

In the course of the return trip of the carrier 16 from the workdelivery position to the pick-up position above the stack for repeatingthe cycle, the chamber 38 is exhausted and the chamber 36 is againprovided with its lower pressure.

Having thus described our invention, what we claim as new and desire tosecure by Letters Patent of the United States is:

l. A pick-up device for transferring single plies of flexible fabric orthe like from a stack, comprising a presser foot, a mounting meansyieldingly holding the presser foot for relative movement toward andfrom a surface of the stack, a work engaging pincer pawl movablysupported by the presser foot for cooperation therewith, the pawl havingoperative connection with the presser foot and having convexly disposedworkengageable teeth, spring means biasing the pawl teeth laterally awayfrom the presser foot to allow a localized portion of an external ply ofthe stack to enter therebetween, and a pinch adjusting nut threaded onsaid mounting means and engageable with the pawl to limit lateralspacing of the pawl teeth from the presser foot, said nut being arrangedduring relative movement of the stack surface and the pawl to cam thepawl toward work pinching relation on the presser foot.

2. A device as in claim 1 wherein the nut has circumferentially spacedformations respectively mateable with a complemental recess in themounting means, and a locking pin detachably receivable in therespective formations and said recess to adjustably determine the nip ofthe pawl.

1. A pick-up device for transferring single plies of flexible fabric orthe like from a stack, comprising a presser foot, a mounting meansyieldingly holding the presser foot for relative movement toward andfrom a surface of the stack, a work engaging pincer pawl movablysupported by the presser foot for cooperation therewith, the pawl havingoperative connection with the presser foot and having convexly disposedwork-engageable teeth, spring means biasing the pawl teeth laterallyaway from the presser foot to allow a localized portion of an externalply of the stack to enter therebetween, and a pinch adjusting nutthreaded on said mounting means and engageable with the pawl to limitlateral spacing of the pawl teeth from the presser foot, said nut beingarranged during relative movement of the stack surface and the pawl tocam the pawl toward work pinching relation on the presser foot.
 2. Adevice as in cLaim 1 wherein the nut has circumferentially spacedformations respectively mateable with a complemental recess in themounting means, and a locking pin detachably receivable in therespective formations and said recess to adjustably determine the nip ofthe pawl.